Coronary artery disease: Pathology review

In an urban emergency department, 3 people came in for chest pain. The first is Anish, a 54 year old man with a known history of hypertension, hyperlipidemia, and 25-pack year smoking. He’s complaining of shortness of breath, and squeezing, retrosternal chest pain that radiates to his neck, jaw and left arm. He’s been having these episodes but they only come after riding his bicycle for at least 20 minutes, and is relieved once he rests. Investigations reveal a normal ECG and normal troponin levels. Next, is Erica, a 66-year old woman with a history of diabetes mellitus who complains of sudden-onset shortness of breath, fatigue and dizziness, but no chest pain. An ECG reveals ST-segment depression, and troponin levels are elevated. Finally, There’s Tyrion, a 45-year old man, with a known history of hypertension, diabetes, and hyperlipidemia. He complains of epigastric abdominal pain at rest, shortness of breath, sweating and lightheadedness for the past 30 minutes. His blood pressure is 80/60, and his heart is 45 beats per minute. An ECG reveals ST-segment elevation in leads II, III and aVF.

All three have coronary artery disease which is defined as an imbalance between myocardial oxygen demand and supply from the coronary arteries. Reduced oxygen supply to the heart is defined myocardial ischemia, which results in a severely reduced ability of the heart muscle ability to contract. If this is prolonged, it can go on to cause myocardial infarction, otherwise known as heart attack, which refers to death of heart muscle. Now, coronary artery disease is usually caused by atherosclerosis of the coronary arteries. Risk factors for atherosclerosis can be divided into non-modifiable ones, which include age, with men greater than 45 years and women greater than 55 years being at risk, and family history of coronary artery disease, and modifiable ones, like lipid abnormalities including elevated LDL or low HDL levels, as well as hypertension, diabetes mellitus and smoking. Coronary artery disease can present in many ways, including stable angina, Prinzmetal angina, acute coronary syndrome - which includes unstable angina, non-ST-segment elevation myocardial infarction, or NSTEMI, ST-segment elevation myocardial infarction, or STEMI, chronic ischemic heart disease, and sudden cardiac death.